Developing photographic films and plates



Patented Oct. 31, 1939 UNITED STATES PATENT OFFICE DEVELOPINGPHOTOGRAPHIC FILMS AND PLATES poration of Delaware No Drawing.Application April 6, 1938, Serial No. 200,432

16 Claims.

This invention relates to photographic developers and methods ofphotographic developmg.

Photographic development, particularly of films, has been subject to anumber of difliculties such as the formation of air bubbles on theemulsion, pin hole formation and uneven development, particularly when arapid developer is used in a day-light developing tank where thesolution is poured in and one portion of the film encounters thedeveloper before other portions. These difficulties are largely due tohigh surface tension of the developer solution. However, the ordinarytype of surface tension reducing materials such as for example ordinarysoaps and the like cannot be used because they are not inert in theprocess.

According to the present invention, the distribution of the developersolution over the surface of the photographic emulsion is effected bythe presence of minute amounts of salts of esters of aliphatic sulphodicarboxylic acids. Among the compounds which may be used are salts ofthe esters of sulphosuccinic, sulphomaleic, sulphoglutaric and othersulpho dicarboxylic acids. The esters may be of various alcoholsdepending ,on the particular acid used. In general, the molecular weightof the alcohols should be greater with sulpho dicarboxylic acids of lowmolecular weight and may be less with those of higher molecular weight.Taking the esters of sulphosuccinic acid as an example, because they arecommercially available, the effectiveness is much lower with the methyl,ethyl, propyl and butyl esters and increases rapidly until the octylester is reached, beyond which the effectiveness slowly decreases. Wehave found that the best material for the present invention is sodiumdioctyl sulphosuccinate which is extremely effective.

The sulpho dicarboxylic acid esters of the present invention have theimportant property that they do not form decomposition products, whichexert any deleterious action on development. This is an important factorbecause on long standing, particularly with developers of high pH, aconsiderable degree of decomposition of the sulpho dicarboxylic estertakes place.

The present invention may be carried .out by two general methodssuitable for diiferent types of developing technique. The simplestmethod for tray development for plates, film packs, cut film and thelike is to subject the material to a preliminary bath in a very diluteaqueous solution of the sulpho dicarboxylic ester. The wetted film isthen transferred to the developer and developed, hardened and fixed inthe usual manner. No change in operating technique is required and theadvantages of complete freedom from pin holes, streaks and otherevidences of uneven development are obtained withoutany sacrifice irremulsion speed, definition, grain size or other desirablecharacteristics of a particular developer or a development technique.When desensitization is employed, the desensitizer such as pinacryptolyellow or green may be added to the preliminary bath in which case, ofcourse, the film or plate should be left in the preliminary bath for asuflicient time to satisfactorily desensitize, which in general will belonger than the time required to thoroughly distribute a film of thedilute solution of the sulpho dicarboxylic ester over the photographicemulsion. It is an advantage of the present invention that the emulsionis not in any way aifected by long contact with the sulpho dicarboxylicester.

The second method which is more satisfactory for tank development,particularly in the daylight tanks where solutions are added in fulldaylight, and in the development of prints, involves the addition of asmall amount of sulpho dicarboxylic ester to the developer. Thiseliminates the necessity of a separate bath but is not universallyapplicable to alltypes of developers as will be pointed out below.

Salts of sulpho dicarboxylic acid esters such as sodium dioctylsulphosuccinate are sensitive to alkali and at high pH values aredestroyed to a considerable extent. Thus, with developers of very highpH such as D-72 and particularly D-ll, D-9 and other high energydevelopers, the effectiveness of the sulpho dicarboxylic ester decreasesafter standing for days and weeks. With developers of lower pH such asD-76, DK-50, Sease #3, Champlin #15 and the like, the effectiveness ofthe sulpho dicarboxylic ester remains for many weeks and even months. Inthe case of developers having a pH of about 53.8-10.0, there isconsiderable decomposition of the sulpho dicarboxylic ester whenstanding for weeks. Typical examples of such developers are D-16, andthe Agfa Tropical developer. Even in the case of these developers, theeffectiveness of the sulpho dicarboxylic ester remains for aconsiderable period of time. i The second method, that is to say wherethe sulpho dicarboxylic ester is incorporated with the developer and notas a separate bath, may also be used even with developers of very highpH in which case a small amount of the sulpho dicarboxylic ester isadded to the developer just before it is used. The decompositionproducts do not harm development and fresh additions maybe -made eachtime the developer is used.

In the case of print development, which usually employs developerssuch'as D-72 having a pH of somewhat over 10.0, the sulpho dicarboxylicester is added to the diluted developer and it is not material that theresulting product does not keep very well since a batch of diluteddeveloper is discarded after an evenings. printing in any event. Theaddition of the sulpho dicarboxylic ester to a strong stock solution ofD-72 is not desirable as it decomposes and loses its activity within afew weeks.

The choice of the particular method of employing the present inventionwill be determined to a large extent by the pH of the developer. In thecase of sodium dioctyl sulphosuccinate, the preferred sulphodicarboxylic ester of the present invention. the critical pH range issomewhere around 9.8. Developers with lower pHs such as D-76, Sease #3,Champlin #15 and the like show excellent keeping qualities and thereforeit is preferable to incorporate the dioctyl sulphosuccinate with thesedevelopers. Developers of higher pH are preferably used with apreliminary bath.

The following examples will illustrate the invention.

Example 1 A bath is prepared containing about 0.25% of sodium dioctylsulphosuccinate. The films or plates to be developed are immersed for ashort time in the bath, then if desired rinsed in a bath of plain waterand developed in the usual manner. Complete freedom from streaks, pinholes and other results of uneven development will be noted. Nostreaking will occur even though a developer of high speed, such asD-72, is employed and even though but little agitation is used.

For convenience, it is desirable to make up a 2% stock solution of thesodium dioctyl sulphosuccinate which is most advantageously made in an80% water, 20% methyl alcohol solution. A small portion of the stocksolution is diluted with water to make up the 0.25% bath.

If desired, desensitization can be effected by incorporating adesensitizer in the bath containing the sodium dioctyl sulphosuccinateor in a bath following it. Desensitization is more rapid and completebecause of the action of the sodium dioctyl sulphosuccinate.

Example 2 D-"76 developer is prepared in accordance with the standardformula published by the Eastman Kodak Company containing 2 gms. ofmetol, 5 gms. of hydroquinone, 100 gms. of anhydrous sodium sulfite and2 gms. oi borax per liter of water. 1 cc. of a 10% aqueous solution ofsodium dioctyl sulphosuccinate is added and the developer used in thenormal manner. For example, in developing a roll of mm. EastmanSupersensitive Panchromatic film, the film is loaded into a day-lighttank, the lights turned on, the developer added and developmentcontinued for 15 minutes with only occasional agitation. An excellentnegative is obtained free from any evidence of uneven development andthe results are in every way comparable to those obtained by continuousagitation, it being an advantage of the present invention thatpractically stagnant development can be used without uneven results. Onstanding for weeks, no substantial change in the developer solution isnoted and it can be reused to the same extent as ordinary D-76developer.

Example 3 A Sease #3 developer containing 10 gms. of pphenylenediamine,6 gms. of glycine and 90 gms. of anhydrous sodium sulfite to the literof water is prepared and 0.75 cc. of a 10% solution or sodium dioctylsulphosuccinate is added. Tank development of 35 mm. EastmanSupersensitive Panchromatic film is carried out as described in Example1, the development time being 27 minutes at 21 C. The development isstagnant and a negative is obtained free from any signs of unevendevelopment.

The developer maintains its desirable properties even on standing forweeks.

Example 4 A Champlin #15 developer containing 3.5 gms. of pyrogallol,gms. of anhydrous sodium sulfite, 1.2 gms. of benzoic acid, 0.5 gms. ofsalicylic acid, 2.5 gms. of boric acid, 1 gm. of digallic acid, 11.5gms. of glycine, 11.5 gms. of p-phenylenediamine, 50 cc. of isopropylalcohol and 1 gm. of nickel ammonium sulfate in a liter of water ismixed with 1 cc. of a 10% aqueous solution of sodium dioctylsulphosuccinate. stagnant tank development of 35 mm. rolls of EastmanSupersensitive Panchromatic film carried out for 27 minutes at 21 C.results in a negative of excellent characteristics showing no trace ofuneven development. The developer retains its characteristics onstanding for weeks.

Example 5 An Agia Tropical developer containing 2.5 gms. of metol, 18gms. of anhydrous sodium sulfite, 6.5 gms. of hydroquinone, 16 gms. ofanhydrous sodium carbonate and 1 gm. of potassium bromide in a liter ofwater is mixed with 1 cc. of 10% aqueous solution of sodium dioctylsulphosuccinate. A cut film of Eastman Supersensitive Panchromatic filmis developed in a tray with full agitation for one and a half minutes at29 C. The film is then hardened with chrome alum hardener and fixed inthe usual manner for tropical development. No sign of uneven developmentis to be noted which is particularly important as the high speed of thedeveloper makes streaking due to non-uniform development more seriousthan in slower developers.

The developer shows considerable loss of characteristics after standingfor several weeks and if permitted to stand for so long a time, a smallamount, for example 0.5 cc., of 10% sodium dioctyl sulphosuccinateshould be added before reuse. 1

Example 6 An Eastman D-16 developer is prepared containing 0.31 gm. ofmetol, 6 gms. of hydroquinone, 39.6 gms. of anhydrous sodium sulfite,18.7 gms. of anhydrous sodium carbonate, 0.86 gm. of potassium bromide,0.68 gm. of citric acid and 1.5 gms. of potassium meta-bisulfite in aliter of water. 2 cc. of a 10% solution of sodium dioctylsulphosuccinate is added and orthochromatic process film developed in atray with full agitation for three minutes at 18 C. An excellentnegative is obtained with no traces of uneven development.

The developer loses but little of its characteristics on standing forseveral weeks.

Example 7 A 13-72 developer for print development is prepared bydiluting D-72 stock solution containing 3.1 gms. of metol, 12 gms. ofhydroquinone, 45 gms. of anhydrous sodium sulfite, 67.5 gms. ofanhydrous sodium carbonate and 1.9 gms. of potassium bromide to theliter of water with 3 to 4 parts of water and adding from 0.2 to 0.3 cc.of 10% solution of sodium dioctyl sulphosuccinate to the liter ofdiluted solution. Paper developed in this developer gives excellentprints with no ment is to be noted in spite of the stagnant tankdevelopment. The developer will keep for a day or two but will not keepfor a longer period of time and should be discarded after use.

Example 8 A developer of the formula of Eastman Kodaks DK-50 is preparedand 1 cc. of a 10% aqueous solution of sodium di(methy1 amyl)sulphosuccinic acid is incorporated. A roll of 2%" by 3 AgfaSuperplenachrome roll film is loaded into a day-light developing tankand 500 cc. of the dedeveloper poured into the tank without agitation.Substantially stagnant development is then carried out for five minutesat 18 C. and the negative then fixed and hardened in the customarymanner. The negative shows excellent detail with no sign of unevendevelopment in spite of the relatively slow addition'of the developingsolution which would normally result in a streaked roll because oflonger development of the portion of the roll in the bottom of the tank.

The developer keeps satisfactorily for weeks but if kept for more than amonth requires the addition of fresh sulphosuccinic ester.

The examples give typical results obtainable by means of the presentinvention with standard developers. It is an advantage of the inventionthat it is equally applicable to all types of films having beensuccessfully used not only on Supersensitive Panchromatic, high speedOrthochromatic and slow speed Orthochromatic films as described abovebut also on slow speed panchromatic and motion picture positive. In thecase of process films and motion picture positive films where highcontrast developers of high pH are often used, the invention givesexceptionally good results because these high energy developers tendtoward uneven development due to their high developing speed.

What we claim is:

1. A method ofdeveloping silver halide emulsions which comprisessubjecting the emulsion containing a latent image to the action of achemical developer together with an effective amount not substantiallyexceeding 0.25% of a salt of an ester of an aliphatic sulfodicarboxylicacid.

2. A method of developing silver halide emulsions which comprisessubjecting the emulsion containing a latent image to the action of abath consisting of an aqueous solution containnig an effective amountnot substantially exceeding 0.25% of a salt of an ester of an aliphaticsuliodicarboxyllc acid and then subjecting the emulsion to the action ofa photographic developing agent.

3. A method of developing silver halide emulsions which comprisessubjecting the emulsion containing a latent image to the action of aphotographic developing solution having incorporated therein aneffective amount not substans tially exceeding 0.25% of a salt of anester of an aliphatic sulfodicarboxyllc acid.

4. A method of developing silver halide emulsions which comprisessubjecting the emulsion containing a latent image to the action of achemical developer together with an effective amount not substantiallyexceeding 0.25% of a salt of an ester of sulfosuccinic acid.

5. A method of developing silver halide emulsions which comprisessubjecting the emulsion containing a latent image to. the action of abath consisting of an aqueous solution containing an efiective amountnot substantially exceeding 0.25% of a salt of an ester of sulfosuccinicacid and then subjecting the emulsion to the action of a photographicdeveloping agent.

6. A method of developing silver halide emulsions which comprisessubjecting the emulsion containing a latent image to the action of aphotographic developing solution having incorporated therein aneiiective amount not substantially exceeding 0.25% of a salt of an esterof sulfosuccinic acid. I

'7. A method of developing silver halide emulsions which comprisessubjecting the emulsion containing a latent image to the action of achemical developer together with an efiective amount not substantiallyexceeding 0.25% of a salt of a dioctyl ester of sulfosuccinic acid.

8. A method of developing silver halide emulsions which comprisessubjecting the emulsion containing a latent image to the action of abath consisting of an aqueous solution containing an effective amountnot substantially exceeding 0.25% of a salt of a dioctyl ester ofsulfosuccinic acid and then subjecting the emulsion to the action of aphotographic developing agent.

9. A method of developing silver halide emulsions which comprisessubjecting the emulsion containing a latent image to the action of aphotographic developing solution having incorporated therein aneffective amount not substantially exceeding 0.25% of a salt of adioctyl ester of sulfosuccinic acid.

10. A photographic developing solution having incorporated therein aneffective amount not substantially exceeding 0.25% of a salt of an esterof an aliphatic sulfodicarboxylic acid.

11. A photographic developing solution having incorporated therein anefiective amount not substantially exceeding 0.25% of a salt of an esterof sulfosuccinic acid.

12. A photographic developing solution having incorporated therein anefiective amount not substantially exceeding 0.25% of a salt of adioctyl ester of sulfosuccinic acid.

13. A method according to claim 3 in which the amount of the salt of analiphatic sulfo dicarboxylic acid ester does not exceed 0.01%.

14. A photographic developer solution according to claim 10 in which theconcentration of the salt of an aliphatic sulfo dicarboxylic acid esteris of the order of magnitude of-0.01%.

muons o. Janeen. JOSEPH n. JEWETT.

